Protherm 100ec Combi Boiler - Water only hot every 30 seconds or so

Hi, ive recently bought a house with what ive been told is less than 3 years old protherm combi boiler.

The hot water from this is very hit and miss despite the central heatin being excellent. If i turn a tap on full, the hot water goes warm, then hot, then warm, then cold, then a bit warmer then hot and repeats the cycle, but not in the same order always. Ive tried running the taps only half open to see if the flow affects it and sometimes, if i start at a low flow and keep it low the water gets extremely hot, other times, its as hit and miss as when the taps are fully open. Confused? yeah, me too :-)

There also seems to be confusion in the boiler itself, because the led display apparently should display the dhw temp when the taps are on, but sometimes this goes to 42 or more, yet the water coming out of the tap isnt hot? when it goes down to low 30's it might be rnning hotter to the touch than it was when the display said 40??!!

please help :-)

Reply to
Tone
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I'm not familiar with this model but the symptoms sound like a temperature sensor problem, the boiler controls probably aren't getting a signal to control the flame modulation and it is running up to a limit stat (separate stat) turning off the flame, cooling down and starting again. Is the installation and service manual available? Try to locate the DHW temperature sensor and ensure that it is in good contact with the hot water pipe/heat exchanger within the boiler, also that it has a good electrical connection to the wiring and if you have a half decent meter check the resistance of the sensor both hot and cold.

Reply to
John

thanks John,

further tests last night show that the following sequence occurs.

Hot water tpa on - Bolier fires up, water goes warm, after around

10-15 seconds, flames visible within the boiler go out, water goes cold, 10-15 seconds again flames come back on water warms up - repeat repeat repeat.

Changing the temperature of the DHW onthe boiler form anything between

40-60 degrees (the full range)does not affect this. Turning the hot water taps on more or less doesnt affect this. Having the Central heating on doesnt change things either.

Are the suggestions you've made fairly easy/safe to perform? This will be my first attempt at maintaining a boiler of any kind :-s

Reply to
Tone

Not being familiar with this model I'm not sure that I ought to push you into the innards. Have you taken the decor casing off to see whats under it yet? In the meantime I'll take a look on Google for the Protherm 100ec

Reply to
John

Google is throwing up all sorts of spurious leads for Protherm. Has anyone any ideas as to the location of the manufacturer?

Reply to
John

A few blind alleys but after some time I found a contact phone number for Protherm/ProRad 01771 828100 Unfortunately this rings out as number not in use. It may be that this company is an ex parrot?

Reply to
John

the company that provides support was indeed charging at a premium rate. 4 mins at 50p/min to tell me i neeeded an engineer to come out and look at it! Great.

the installation company is/was heatcall

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- ive checked their website but still want to see if there is anything i can do to resolve this myself before getting the experts in.

it definitely stays lit for about 10s then goes off. Could this be caused by scaling on the parts? where i live is a bad area for scaling...

Reply to
Tone

Quite possibly. See my posting under the "Combi-boiler Hotwater 'heat dump' too hot" thread.

Reply to
Ed Sirett

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